Aubergine iCLIP Reveals piRNA-Dependent Decay of mRNAs Involved in Germ Cell Development in the Early Embryo

Abstract : The Piwi-interacting RNA (piRNA) pathway plays anessential role in the repression of transposons inthe germline. Other functions of piRNAs such aspost-transcriptional regulation of mRNAs are nowemerging. Here, we perform iCLIP with the PIWIprotein Aubergine (Aub) and identify hundreds ofmaternal mRNAs interacting with Aub in the earlyDrosophilaembryo. Gene expression profiling re-veals that a proportion of these mRNAs undergoAub-dependent destabilization during the maternal-to-zygotic transition. Strikingly, Aub-dependent un-stable mRNAs encode germ cell determinants. iCLIPwith an Aub mutant that is unable to bind piRNAsconfirms piRNA-dependent binding of Aub tomRNAs. Base pairing between piRNAs and mRNAscan induce mRNA cleavage and decay that areessential for embryonic development. These resultssuggest general regulation of maternal mRNAs byAub and piRNAs, which plays a key developmentalrole in the embryo through decay and localizationof mRNAs encoding germ cell determinants